Broken bones heal naturally, albeit slowly, compared to most soft tissue, provided they are adequately supported and relieved of stress. In a simple break in an extremity, adequate support and relief may be provided from outside the body with a device as simple as a splint or a cast, which immobilizes the body part containing the broken bone. Such procedures may suffice when the bone can be set and will retain its position without significant intervention, for instance when the break is simple and contained in a body part that can be readily immobilized in a natural posture. Immobilization is also therapeutic to treat damage to connective tissue by preventing repetitive stress and further injury to, for instance, damaged ligaments, tendons, or cartilage. Degenerative conditions may also be treated with immobilization, and particularly degenerative conditions of the spine. For example, spinal degenerative conditions may include slipped, herniated or ruptured discs, spinal stenosis, osteoarthritis, degenerative disc disease and other conditions. Misaligned vertebrae, or vertebrae repositioned in the course of reconstructive surgery, may also be immobilized permanently or temporarily to support the spine during healing or spinal fusion.
When a break, fracture, degenerative condition, or misalignment affects the spine, or when the connective tissue between one or more vertebrae is damaged, external immobilization is significantly less effective for several reasons. Because the spine is the central support column of the human body, externally imposed immobilization is impractical, as it implies immobilizing most of the body. Furthermore, the spine is aloud-hearing structure that is subject to repetitive compressive and rotational stresses constantly during the normal waking life of a person; therefore, external immobilization of the spine significantly impacts the mobility and activity of a patient. For practical purposes, externally imposed spinal immobilization often requires that the patient is subjected to bed rest, is wheelchair-bound, is fitted with a significant amount of uncomfortable stabilizing equipment, or a combination of the above.
Since the advent of sterile surgery, it has been possible for doctors to internally stabilize broken bones and connective tissue with implants. Internal stabilization can be complex, but tends to allow much greater precision in aligning broken bones, and significantly reduces misalignment in healing. Internal stabilization also improves healing time and allows a patient to live a much more normal life while still healing. One such type of implant is a bone plate, which is a shaped rigid or semirigid part usually having several through-holes by which a surgeon will attach the plate to parts of a broken bone, or to parts of two or more proximate bones that require alignment, using screws.
Various aspects of the surgical procedure of installing a bone plate impact patient outcomes. For example, the bone plate must be properly aligned with the underlying bone, and retained in alignment during attachment. Also, the duration of an installation procedure, and the tissue displacement required for the procedure, should be minimized as much as practicable to minimize trauma. The tools and methods for inserting and stabilizing a bone plate for surgical insertion and revision very much impact these aspects of the surgical procedure.